Field of the Invention
The present invention relates grading systems for grading objects, based on conveyor equipment with ridge-belts. The device and the method make possible to adjust the gap width of such grading systems more precisely and accurately than current technology allows.
Brief Discussion of the Related Art
The process of grading objects such as small and delicate marine species or fruit can be a problem due to their small size and the volume to be processed at each time and the fact that the quality of the food items deteriorates quickly upon rough handling procedures. An efficient grading process is therefore required based on selection criteria such as size and/or the sex.
Several different types of grading devices are known for grading fish and food items, which grade the items according to an assessment of their thickness. The known devices are based on belts and rollers as well as shaker-graders, which use several grading channels.
WO9641541 discloses a grading device based on specially-designed conveyor equipment so-called ridge-belts, which move the objects forwards without shaking or rubbing the items during the grading process. Such grading devices are designed so that the grading channels are narrower at the in-feed end (receiving end) than at the outlet end. This device allows for more gentle treatment of the objects to be graded, with a high processing rate. The problem solved by using this grading device is that the material is arranged into a single layer in optimal position onto the grading apparatus. This ensures that small items are not carried on top of larger items into a wrong grading compartment.
The adjustment of the channel width both at the intake and the outlet end is an important aspect of this technology. The channel width is set before the grading process is started, but sometimes the channel width needs to be adjusted or fine-tuned during the grading process. This requires a solution, where the channel width can be set before and during the grading process in a manner such that the channel width is the same between in all the channels on the grading device. W0 2006/120706 discloses a setting device being a more efficient solution to set and adjust or fine-tune the channel width of ridge-belts of grading devices in a more precise and accurate manner. The setting or adjusting device is implemented perpendicular underneath the belts of the apparatus comprising alternatively arranged support members and adjusting members arranged on an adjusting screwing shaft. Both components comprise screwing sections which regulates an increase or a decrease in the gap between the support members when the adjusting screwing shaft is rotated. A problem with this technology is that the various components of the adjusting device, especially the components that interact with each other by a screwing mechanism collect debris, particles, dirt and water which affects the adjusting or setting mechanism and can affect the mechanism and are the perfect setting for bacterial growth.